1. Field of the Invention
The present invention relates to intraluminal endoprosthetic devices. In particular, the present invention relates to ostial intraluminal endoprosthetic devices and delivery systems and methods for deploying them.
2. Description of Related Art
Stents are prosthetic devices that are implanted in the lumen of a vessel inside the body to provide support for the wall of the vessel. Typically, stents are implanted within a vessel system to reinforce vessels that are partially occluded, collapsing, weakened, or abnormally dilated. In some cases, stents may be used to address ostial lesions in renal, subclavian, carotid, LCA, RCA, and SVG coronary bypass graft anastomosis sites, as well as in other locations. More generally, stents can be used inside any physiological conduit or duct, including arteries, veins, bile ducts, the urinary tract, alimentary tracts, the tracheobronchial tree, a cerebral aqueduct or the genitourinary system, for example. Stents may be used in both humans and animals.
There are typically two types of stents: self-expanding stents and balloon-expandable stents. Self-expanding stents automatically expand once they are released and assume a deployed, expanded state. A balloon-expandable stent is expanded using an inflatable balloon catheter or other balloon delivery device. The balloon is inflated to plastically deform the stent. Balloon-expandable stents may be implanted by mounting the stent in an unexpanded or crimped state on a balloon segment of a catheter. The catheter, after having the crimped stent placed thereon, is inserted through a puncture in a vessel wall and moved through the vessel until it is positioned in a portion of the vessel that is in need of repair. The stent is then expanded by inflating the balloon catheter against the inside wall of the vessel. The stent is plastically deformed by the inflation of the balloon so that its diameter increases and remains at an increased state. In some situations, the vessel that the stent is implanted into may be dilated by the stent itself when the stent is expanded.
Balloon-expandable stents are more easily and more accurately positioned because they can be expanded slowly, uniformly, and without undue movement axially during placement. A balloon-expandable stent may be moved within a vessel even after it has started to expand. In contrast, self expanding stents are more difficult to position and more difficult to move once they have started to expand. Self expanding stents, while more difficult to align and accurate place within a vessel do have some advantages, particularly when addressing ostial lesions in vessels. Self-expanding stent exert continual outward radial force and form a “pre-determined” shape or diameter. This is particularly useful when trying to address ostial lessions.